Computational complexity reduction techniques for real-time and high-resolution medical ultrasound imaging using the beam-space Capon method

The beam-space (BS) Capon method is an adaptive beamforming technique that reduces computational complexity. However, the complexity is not low enough for real-time imaging. Reducing the number of time-delay and transformation processes from element-space to BS signal processing is required. We propose a technique that replaces the time-delay processes by the multiplication of steering vectors and covariance matrices. In addition, we propose a compensation technique for estimating the intensity accurately. In an experimental study using a 2.0MHz transmission frequency on a 15 × 10.4mm² region of interest, the first side-lobe level, the %6 dB beam width, the intensity's estimation error, and the calculation time of the conventional method were %15 dB, 0.70 mm, 3.2 dB, and 656 ms. Those of the proposed method were %17 dB, 0.36mm, 1.6 dB, and 81ms, respectively. Using our method on three CPUs achieves imaging of 37 frames/s.